From Propagation Channel to Radio Channel: Beamforming Impact on Millimeter-Wave and Sub-Terahertz Wireless Transmission

To design a millimeter-wave/sub-terahertz wireless system, it is essential to understand the radio channel in which it will operate rather than the propagation channel. Radio channel consists of antennas and radio front-ends, in addition to propagation channel. In this paper, a framework of involving beamforming impact for radio channel characterization is introduced using multi-band measured and simulated propagation channel data. On the beamformed channel, we propose a beam direction-based channel similarity metric for the evaluation of multi-band channel similarity, as well as uplink and downlink channel reciprocity. The beamforming impact on time dispersion of measured sub-THz channels is also analyzed for radio interface design and parametrization.